1. Field of the Invention
The present invention relates to a retardation layer (or film) and an organic light-emitting device including the retardation layer.
2. Description of the Related Art
Organic light-emitting devices are self-emissive devices (i.e., they do not need to use a backlight unit). The organic light-emitting devices have relatively higher brightness than liquid crystal displays and can be formed to be relatively thin because no backlight unit is used.
However, organic light-emitting devices have relatively low contrast due to light reflected therefrom when images are viewed in bright environments (e.g., in sunlight).
One way of improving contrast in organic light-emitting devices is to use a circular polarizer.
A circular polarizer used in conventional organic light-emitting devices is in the form of a film, and is formed by attaching a linear polarization film and a quarter (¼) wavelength layer to an image display surface using an adhesive. However, it is difficult to form such a film-type circular polarizer to be thin because it includes films and an adhesive layer. Moreover, images must be transmitted through all films constituting a circular polarizer, even through an adhesive layer, thereby decreasing light extraction efficiency, resulting in a reduction in brightness.